Papers by Author: Sung Min Joo

Abstract: Homogeneous precipitated calcium carbonate(PCC) was synthesized by calcinations, hydration and carbonation of limestone which has been deposited in Danyang, Korea. In the reaction process, shapes(scalenohedral and cubic) and sizes(0.2~0.3μm and 2.0μm) of the powder were controlled by reaction temperature. Synthesized PCC was applied to hand-made paper as filler and coated paper. For the prepared papers, physical/optical properties(brightness, whiteness, opacity, roughness, gloss, tensile strength, internal tearing strength, stiffness, bursting strength) and printability(ink gloss, ink set-off, dry pick, wet pick) were characterized

Abstract: The purpose of this work is to influence of CaO concentrations of 5.0 wt.% and 10.0 wt.%, slurry feeding rate of 200~400
/min, rotating rate of drum of 5,000 and 10,000 rpm, inlet and outlet temperature on the synthesis of Ca(OH)2 powder, and the synthesis of precipitated calcium carbonate by carbonation process using Ca(OH)2 prepared by spray drying method. As the feeding rate of slurry was increased, the particle size of Ca(OH)2 was decreased. Regardless of rotating rate of drum, when the concentration of CaO was 5.0 wt.% and 10.0 wt.%, the morphology of Ca(OH)2 showed spherical shape of 10~30 μm and 20~60 μm, respectively. The specific surface area of synthesized Ca(OH)2 was 27~30 m2/g. When the initial reaction temperature was 11 °C and 30 °C, the shape and particle size of precipitated calcium carbonate synthesized in the carbonation process showed the rectangular shape of 0.1~0.4 μm and the spindle shape of 0.5~1.0 μm, respectively.

Abstract: The effect of the impurity ions Al3+, Fe3+ and Mg2+ on the formation yield and crystal properties of precipitated calcium carbonate(PCC) produced by the carbonation process was investigated in Ca(OH)2-H2O-CO2 system. The effect of the impurity ions Al3+, Fe3+ and Mg2+ on the formation yield using particle size distribution and morphology of PCC were discussed. The particle size distribution of PCC was increased with increase of impurity ions. The morphology was transformed in order of spheroidal, scalenohedral, rhombohedral calcite for Al3+, Fe3+ and rhombospheroidal, spherical, scalenohedral for Mg2+ with increase of impurity ions.

Abstract: Non-isothermal behaviors of calcium carbonate using Danyang limestone were investigated. It was attempted to provide non-isothermal data with a precision sufficient for the determination of reliable decomposition behaviors and for the estimation of accurate kinetic parameter. The decomposition temperature of calcium carbonate on the onset, peak and final point were measured. Reaction rate was decreased and maximum reaction temperature was increased with increasing heating rate. Activation energy of Danyang limestone was 45.14㎉/㏖ and 50.80㎉/ ㏖ by Kissinger method and Freeman method, respectively.